STATE COLLEGE — Former Penn State defensive coordinator Ted Roof won’t forget his one season in Happy Valley.

But home is home. And after the opportunity arose quickly to take the same position at his alma mater, Georgia Tech, he said he made the difficult decision to leave the Nittany Lions and return to his native Georgia.

“That was a real privilege and special deal for me to be part of that football team,” Roof said about the 2012 Penn State season in a phone interview Thursday with The Associated Press. He called it a special year and the team a “special group of guys.”

The move appeared to catch most people around the program by surprise. Roof said the opportunity at Georgia Tech only surfaced about two days ago.

In a statement Wednesday, Georgia Tech said Roof’s hiring won’t become official until a background check is completed, likely next week.

Roof played for the Yellow Jackets, and was an assistant under former coach George O’Leary, as well. O’Brien was also on that Georgia Tech staff. Roof was the head coach at Duke from 2003-7, where the Blue Devils went just 6-45.

A year ago, O’Brien lured Roof to State College just weeks after Roof had taken the defensive coordinator job at Central Florida under O’Leary. He was one of O’Brien’s first hires as the new coach began shepherding the Nittany Lions through the rocky aftermath of the Jerry Sandusky child molestation scandal.

At 8-4, this season turned out to be a success for O’Brien and Roof — especially given the scrutiny around the team after the NCAA handed down its sanctions over the summer.

Already known for good defense, Roof tweaked the Nittany Lions’ schemes with more blitzes. Under his watch, Penn State was second in the Big Ten in scoring defense (19.1 points), first in sacks (34) and first in red-zone defense. He was also instrumental in opening up recruiting avenues in the South for Penn State, including the trail that led to backup quarterback Steven Bench, of Georgia.

Roof appeared to forge strong bonds with players, including senior linebacker Michael Mauti, during the stressful year. He said this team would be remembered “because of the heart and commitment that they showed and exhibited ... Everything that’s right about college football.”

When asked if there were any hard feelings in his departure, Roof quickly said “Absolutely not.”

O’Brien, in a statement Wednesday, praised Roof and wished him well: “Ted is a great coach and person. He earned the respect of our players and they enjoyed playing for him.”

Now Butler will be Penn State’s third defensive coordinator in three years. Tom Bradley was the defensive coordinator for 11 seasons but wasn’t retained when O’Brien took over.

Butler was a linebackers coach at Minnesota in Roof’s one season there as defensive coordinator in 2008.

“There’s no doubt he will do a great job,” Roof said about Butler’s new role. “He’s been ready for that a long time.”